System for determining network structure and positions of mobile devices in a wireless communication network

ABSTRACT

The present invention relates to a solution for determining the location of a mobile communication device in a wireless communication network and for determining a network structure of the wireless communication network using a system of plurality of receivers acquiring radio signals from units in the communication network within a geographical area and triangulating the location of the units. The device may be arranged to trigger a re-establishment of connections between units in order to force communication control signal traffic which can be monitored.

TECHNICAL FIELD

The present invention relates to a system, devices and method fordetermining a network structure and position of a mobile station withinor outside an area of coverage of a wireless communication network.

BACKGROUND OF THE INVENTION

With the advent of wireless telecommunication equipment newpossibilities of communication use has been developed and used by bothgood parties and parties that use these possibilities for illegalpurposes. For instance the modern telecommunication technology may beused for crime, threats or terrorism. In these situations it is ofinterest to build a picture of the static and dynamic network structurein order to assess the situation and possibly control communicationlinks, e.g. stop certain mobile phones or keep track of certain mobilephones both logical and physical (geographical) connections. Also, itwould be of interest to know the different base stations that is presentin the area of interest and if possible their locations. Operators todaycan provide information about singular mobile phones within a cellconnected to a base station and even information about the position of acertain mobile phone using triangulation of signals from the mobilephone to several base stations within the operator's network.

Furthermore, this type of information is available from the operator oroperators of the networks and this may hamper the information exchangein some situations since it may be difficult to obtain a rapid pictureof the current network structure or some operators may be reluctant toprovide such information. In some cases it will be difficult sinceconnections to all operators operating within a certain area need toopen and information readily available. This is not the case if there isan emergency situation where the infrastructure has been disconnected ordisabled in some way, for instance in a disaster situation such as afteran earthquake, acts of terrorism or war, explosions and so on. In thesetypes of situations time it is very critical and even if theinfrastructure is operating in a sufficient manner, rescue workers maynot have time to rely on the operators to supply essential informationabout all mobile stations in an area.

SUMMARY OF THE INVENTION

It is therefore the object of the present invention to provide asolution for determining the position of individual mobile stationsand/or network structure within a geographical area that is independentof communication with any operators and/or infrastructure devices. Thisis provided for in number of aspects, wherein a first is a system fordetermining the position of mobile stations, the identity of these, theposition of bases stations, and the pairing of mobile stations and basestations to determine physical connections.

This system for finding the structure and/or geographical position ofcommunication units in at least one wireless communication network, maycomprise:

-   -   at least one receiver for acquiring radio signals from the        wireless communication units; and    -   a controller for collecting information related to acquired        signals; characterized in that the at least one receiver is        arranged to acquire radio traffic information within the at        least one communication network and to send the acquired radio        traffic information to the controller for further analysis in        order to determine the network structure and/or geographical        position of wireless communication units.

The may further be arranged to pair mobile stations in communicationwith each other or with gateway units within the mobile communicationnetwork.

The system may further comprise a plurality of receivers in order toacquire signals for triangulation analysis.

The system may further comprise a transmitter arranged to send a signaltriggering a re-establishment of connections between units in thewireless communication network.

The transmitter may be arranged to operate independently of any networkbased permissions between communication units.

The receiver may be arranged to operate stand alone from anyinfrastructure communications network and is arranged to participate ina local communications network formed by the at least one receiver andcontroller.

The receiver may be arranged to acquire signals independent of serviceagreements of the communication units.

Another aspect of the present invention, a detection device for findingthe physical network structure of a wireless communication network isprovided, comprising a receiver for acquiring radio signals fromcommunication units within the network, a communication interfacetowards at least one other detection device for receiving informationabout radio signal acquired by the at least one other detection device,and a processor arranged for executing triangulation processing of databased on acquired signals.

The device may further comprise a transmitter arranged to send a signaltriggering a re-establishment of connections between units in thewireless communication network.

The signal causing re-establishment may comprise at least one of ajamming signal and a protocol command signal. The processor may furtherbe arranged to analyze communication traffic between units incommunication between each other within the network. The device mayfurther comprise means for acting as a base station for the mobileunits. The device may further comprise a direction sensitive antenna.

Yet another aspect of the present invention, a method for finding thenetwork structure of or location of units in a wireless communicationnetwork is provided, comprising the steps of:

-   -   arranging a plurality of receivers arranged to listen and        identify radio traffic in the wireless communication network;    -   obtaining communication traffic using the plurality of        receivers;    -   acquiring obtained traffic in a control unit;    -   analysing the communication traffic in the control unit;    -   triangulating locations for the units within the network.

The method may further comprise a step of forcing re-establishment ofconnections between the mobile stations and the communication networkprior to acquiring communication traffic using the plurality ofreceivers.

The method may further comprise the step of determining mutualconnections between units in the network. The method may furthercomprise the step of determining locations as coordinates in a map andin height.

Still another aspect of the present invention, a communication unit foroperation in a wireless communication network is provided, comprising atleast one communication interface and a processing unit arranged totransmit information stored in a memory about the communication unit toat least one stand alone position detection receiver.

The information stored about the communication unit may comprise atleast one of ID of communication unit, ID of user, health information ofthe user, equipment related to the communication unit or the user, andstatus information of the user.

The invention provides several advantages when it concerns findingpeople in a geographical area since it is possible to detect people withmobile stations (e.g. cell phones) and it is therefore not necessary toequip them with specialized transponders. It is possible to determinethe network structure of a communications network and provideintelligence about this network. This can be provided without theinfrastructure of the network being operational or even aware of asearch or network detection being conducted. It can also be done at lowcost and using limited resources available using stand alone equipment.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following the invention will be described in a non-limiting wayand in more detail with reference to exemplary embodiments illustratedin the enclosed drawings, in which:

FIG. 1 illustrates a system according to the present invention in anexample of a network;

FIG. 2 illustrates a detection device according to the presentinvention;

FIG. 3 illustrates a method according to the present invention;

FIG. 4 illustrates a second embodiment of the present invention; and

FIG. 5 illustrates a communication unit according to the presentinvention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In FIG. 1 reference numeral 1 generally indicate a base station for awireless communication network cell and 2-4 mobile stations locatedwithin the an area 7 wherein it is of interest to detect mobile stationsand base stations 1. Communication receivers 8-10 are shown in FIG. 1and used for receiving signals from the mobile stations and basestations within the area that is under surveillance. The receivers 8-10are controlled by a control unit 11 located in the network as anindependent unit, as part of one communication receiver 8-10, orindependently on an external network 12 connected to the receivers 8-10.The connection between the receivers 8-10 on one hand and the externalnetwork 12 on the other hand can be maintained either through a wirelesscommunication link using one of the base stations 1 under surveillanceor some other wireless communication gateway (e.g. another base stationnot under surveillance, a mobile communication satellite), or using astand alone wireless interface used only between the receivers (usingeither a standard or proprietary wireless protocol), or the connectionmay also be of a wired type. The receiver can together form a localcommunication network together with the controller 11. In case of thecontroller located as part of one of the communication receivers thecommunication between the communication receivers may be any suitableradio interface with sufficient range and communication bandwidth. Thepresent invention may operate as a stand alone system or devicedisconnected to any external network for providing redundancy andindependency from possible bottle necks. The communication receiver maybe equipped with a directional antenna to facilitate detection ofdirection of mobile station and base stations within detection range ofthe receiver. This is indicated in FIG. 1 for the receiver referenced as10. It should be understood that none, all or only part of the receiversused together may be equipped with a directional antenna (i.e. anantenna with a directional sensitivity being able to determine thedirection received signals comes from). The receiver will operateindependently on any service agreements existing between communicationunits; i.e. for instance operator/service provider connection of mobilestations 2, 3, 4, e.g. normally a mobile station is logically andbusiness wise connected to a service provider and roaming to otherservice providers within a country of origin is not permitted whereasthe present invention will not depend on any such service agreements butis arranged to receive signals from mobile stations belonging to anyservice provider. The receiver may be arranged to change thecommunication protocol to adapt to network under surveillance or inorder to communicate with mobile stations using any suitable radiocommunication interface.

The present invention is operating in a mobile communication networkstructure, for instance a GSM, GPRS, UMTS, CDMA2000, Tetra, APCO P25,EDACS, iDEN or similar networks or it could also be other wirelessnetworks for instance built up by Wireless Local Area Network (WLAN)solutions using for instance 802.11, 802.15, or 802.16 series ofwireless communication protocols. The invention is applicable to anysuitable standard or non standard wireless communication method that canbe detected. There is no need for any special adaptation of anyinfrastructure or mobile devices present in the network under scrutinysince the system may operate stand alone without any special cooperationfrom these parts of the network. The system according to the presentinvention passively listens to the radio traffic within the network(s)to determine the structure of the network and/or the location of thedifferent devices present within listening range of the receiver.However, in some cases in order to determine the location of mobilestations in the network, the communication may be required to be active,i.e. the mobile stations communicate directly with at least one of thecommunication receivers, or semi-active, i.e. the communicationreceivers ensures in some way that all mobile stations re-establishcontact with infrastructure units in the network, e.g. through a jammingsignal detaching mobile stations from the communications network, orthrough a reset procedure making sure initial communication to attachthe mobile station to the communication network takes place and thus canbe traced.

FIG. 2 illustrates a receiver according to the present invention. Thereceiver 20 comprises at least one processing device 21 for runningprogram code for controlling the measurement and communicating with thecentral unit. The receiver may further comprise at least one storageunit 22, advantageously of non-volatile type, such as Flash or hard diskmemory; the receiver may also comprise a volatile memory (e.g. RAM ofany suitable type) 23 for temporary storage of data, program code andinstruction sets. The receiver also has one or several interfaces 24 forreceiving radio signals from the network under surveillance; theinterface 24 may also be used for transmittal of radio signals. In someembodiments the control unit and the receiver is located within the samehardware unit and in this case the processing unit is also adapted tohandle program code for communicating control signals and collected datawith the other receivers in the system. Furthermore, the control unitmay be adapted to interface with the user through different types ofinterface solutions 25, such as a computer like keyboard, interfacedevices (e.g. buttons, dials, switches and similar), or through acommunication interface 26 where the user if the system is operatingsoftware on a laptop or other computing device in turn controlling thecontrol unit. FIG. 4 illustrates a system where a receiver 10 iscontrolled by a laptop 41 through a communication interface 42 (e.g. USBUniversal Serial Bus), RS232, RS485, RS422, printer port, or Firewireport). Also, the stand alone receivers may be equipped with similarinterface solutions. It should also be understood that the communicationinterface 42 may be of any suitable kind and is not limited to the abovementioned, for example it may also be other serial interfaces such asCAN bus, Intellibus, SPI bus, FlexRay, and I2C bus. The communicationinterface 42 may also be of a wireless type such as using Bluetooth orWLAN. The receiver can be designed into any suitable type of equipmentsuch as but not limited to a handheld device, a standalone weatherprotected device, or a vehicle mounted device.

The user may control a number of different parameters of the receiverand/or control unit, for instance frequency ranges to scan in,communication protocols to scan, what type of collected data to readand/or store, geographical range, amplitudes to scan, number ofoperators and/or specific operator(s), number of mobile stations tooperate with, active/passive mode of the device, and so on. The receivermay also be arranged to automatically choose at least some of theparameters depending on the settings entered by the user, for instancethe receiver may be arranged to determine which communication protocolsthat can be detected and the user chooses one or several of these andthe receiver may then choose appropriate configurations and parametersaccording to this choice.

The receiver may be arranged with a transmitter for transmitting controlsignals in the wireless communication network wherein it is operating orlistening to traffic in. This may for instance be of use if the receiverwould need to trigger mobile units that are connected to theinfrastructure network of interest but which are not sending anymessages on established channels. The receiver may then transmit ajamming or disturbance signal of any suitable kind in the network inorder to enforce updates from all connected mobile stations, this may bedone for instance by transmitting a signal strong enough to blockcontrol signals between the infrastructure and the mobile stations whichwill enforce them to re-establish contact with each other. The receivermay also force a disconnection of the mobile stations through thejamming or signal or transmittal of disconnection control command andthen act as a base station to which the mobile stations attach to. Thislast procedure is especially useful in a scenario where theinfrastructure network has been disrupted (e.g. in a disaster area).

The receiver may also be arranged to receive an identification signalfrom each unit in the network, for instance the IMSI of each mobilestation. Likewise, the units in the network is often arranged totransmit their unique identification (ID) or they may optionally bearranged with means for transmitting a unique ID. The mobile stationsmay also be arranged to transmit other useful information apart from theunique ID, this may for instance be information about the user such asmedical information that might be useful to rescue workers, e.g.diabetes or heart condition that require special medical attention. Thiscan also be used in a military application of the invention, where eachsoldier, transportation device or even individual equipment can be foundusing the invention and extra information can be extracted about theperson or device holding a mobile station with such informationavailable. Other useful information may be, but not limited to,installed equipment on a device or person (e.g. soldier or rescueworker), equipment performance, person status (e.g. working hours, rank,position, or skills), or anything else that could be of interestdepending on situation (rescue team, military application). In this casethe communication units in the network need to be included with asolution for distributing this type of information. Such a communicationunit (50) is illustrated schematically in FIG. 5.

FIG. 5 illustrates in a schematic block diagram a communication unit(mobile station, base station, access gateway) 50 according to thepresent invention, wherein a processing unit 51 handles user commands,communication data and communication control information. Thecommunication unit 50 may further comprise a volatile (e.g. RAM) 52and/or non volatile memory (e.g. a hard disk or flash disk) 53, and auser interface unit 54. The communication unit 50 may further compriseat least one communication unit 55 and may further comprise a secondcommunication unit 56, each with a respective connecting interface. Allunits in the communication unit can communicate with each other directlyor indirectly through the processing unit 51. It should be noted thatthe communication units may be implemented into the same hardware unit,for instance dual access technologies may be implemented into the samemicroelectronic device or it may be implemented into a device handling asoft radio application (i.e. where the radio coding is controlled to alarge extent in software).

With a unique ID transmitted and received it is possible to excludemobile stations from a search list, for instance if a person is found ina rescue operation but the mobile station is still transmitting from acollapsed building, the rescue workers may decide to not search in thatlocation primarily but concentrate first on locations where mobilestations is located using the solution according to the presentinvention and where the mobile stations are identified and connected topersons still missing. This may facilitate the rescue workers operationby helping them to prioritize more easily.

FIG. 3 illustrates a method according to the present invention.Depending on measurement setup the user or program code in the centralunit may decide on frequencies and communication protocols that are ofinterest and this information is sent to the receivers. In some casesthe receivers need to jam or disturb the radio connections between themobile stations and the infrastructure in order to enforce are-establishment between the mobile stations and the infrastructure. Thereceivers scan and listen at the decided communication frequencies andprotocols. When a sufficient amount of data has been collected or attimely intervals (e.g. streaming as they are collected, once every10^(th) second, every minute or any other time range suitable withrespect to information collection and/or storage capacity), thecollected data is sent to the central unit for further analysis,correlation, calculations and pairing. Finally the result is displayedfor the user of the system, for instance graphically on a map or as textbased information. Different types of analysis may be provided in thesystem, for instance correlation between mobile units and base stations,calculating geographical locations using triangulation data, pairing ofmobile user, i.e. who is communicating with whom, or which mobilestations that are communicating with what base stations in the area.Other information may be of interest such as statistical informationabout the network topology, capacity in each cell for separate operatorsand so on.

The steps of the method can be summarized as follows:

31. A user determines what type of detection is to be conducted and theparameters of interest for this type of detection;32. Optionally, the system can force a re-establishment of the units inthe network under surveillance;33. Acquiring radio signals from the units in the network;34. Sending the acquired radio signals to a controller;35. Analysing the radio signals;36. Triangulating locations of the units in the network.

In calculating the geographical location of mobile stations and basestations it is possible to determine 2 dimensional locations (forinstance as map coordinates) as well as 3 dimensional locations(including height information) using a proper placement of the receiversand an appropriate number of receivers. The receivers are advantageouslylocated in different locations in order to provide an efficienttriangulation and in order to obtain height information they are alsoadvantageously located at different heights (as compared to a referenceplane, e.g. the sea level). For determining height information more thanthree receivers may advantageously be used. The receivers may use GPS(Global Positioning System) data or similar absolute positioninginformation to obtain more accurate data and/or to be independent onlocal positioning services (such as for instance mobile phone basestations). It is advantageous to be independent on local services sincethen the solution may be operated in areas where these have beendisabled or where it is of interest to operate redundantly.

Collected information may be used for instance for competitor analysis.However, another usage for the invention may be for governmentalpurposes for instance for law enforcement agencies to monitor mobilecommunication networks for illegal activities such as acts of terrorism,bank robberies, riots and so on. The law enforcement agency may then beable to pair users, through legal intercept or other means, with eachother within certain areas of interest to closely follow potential userwith criminal intent. It is also possible to in an emergency situationprovide information about location of mobile stations (end thuspotentially the users of these).

The collected data information may also be paired with information fromCall Data Records (CDR) for various purposes such as capacity andbilling purposes but also for user behaviour analysis.

The solution according to the present invention may be utilized in anumber of interesting areas of interest, such as mentioned forcommercial activities or rescue activities. However, the invention andthe embodiments of the invention are not restricted to these applicationareas, but can also be utilized in military application areas: forinstance for determining the network structure of an internalcommunication network between units within a battle field or foracquiring the structure of the opponent in a given location. It alsoapplicable to determine the location of individual soldiers in a givenarea of coverage if the soldiers have individual communication deviceswhich transmit signals which the receivers according to the presentinvention can receive.

The invention can be used in at least two different modes:

-   -   1. location of mobile stations/transponders in within listening        range of the receivers; and    -   2. network structure detection.

These two different types of modes allows for different usage: the firstis suitable for finding mobile stations in an area where networkcoverage is bad or non-existing, for instance in a disaster area or inlocations where mobile network coverage normally is of low quality (e.g.in a forest, for instance when locating a person that has become lost inthe forest) whereas the second mode is more suitable for intelligencework of network structure and competitor analysis. It should be notedthat in the first mode the mobile stations function as a transponder,not that different from for instance avalanche transponders.

It should also be understood that the two modes can of course operate inthe other application as well, depending on what is required and whattype of information is wanted.

With the term wireless communication unit is meant a unit thatcommunicates using a wireless interface (e.g. radio or optical based);however, the unit may also at the same time be connected to a wiredcommunication network and/or a power supply. For instance, a basestation may communicate with mobile stations using a radio interfacewhile at the same time be connected to a fixed network with a wiredconnection.

It should be noted that the word “comprising” does not exclude thepresence of other elements or steps than those listed and the words “a”or “an” preceding an element do not exclude the presence of a pluralityof such elements. The invention can at least in part be implemented ineither software or hardware. It should further be noted that anyreference signs do not limit the scope of the claims, and that several“means”, “devices”, and “units” may be represented by the same item ofhardware.

The above mentioned and described embodiments are only given as examplesand should not be limiting to the present invention. Other solutions,uses, objectives, and functions within the scope of the invention asclaimed in the below described patent claims should be apparent for theperson skilled in the art.

1. A system for finding a the structure and geographical position ofcommunication units in a wireless communication network, comprising areceiver for acquiring radio signals from the wireless communicationunits; and a controller for collecting information related to acquiredsignals; the receiver being arranged to acquire radio trafficinformation within the communication network and to send the acquiredradio traffic information to the controller for further analysis inorder to determine the network structure and geographical position ofcommunication units.
 2. The system according to claim 1, wherein thesystem is further arranged to pair mobile stations in communication witheach other or with gateway units within the mobile communicationnetwork.
 3. The system according to claim 1, wherein the systemcomprises a plurality of receivers in order to acquire signals fortriangulation analysis.
 4. The system according to claim 1, furthercomprising a transmitter arranged to send a signal triggering are-establishment of connections between units in the wirelesscommunication network.
 5. The system according to claim 4, wherein thetransmitter is arranged to operate independently of any network basedpermissions between communication units.
 6. The system according toclaim 1, wherein the receiver is arranged to operate stand alone fromany infrastructure communications network and is arranged to participatein a local communications network formed by the receiver and thecontroller.
 7. The system according to claim 1, wherein the receiver isarranged to acquire signals independent of service agreements of thecommunication units.
 8. A detection device for finding a physicalnetwork structure of a wireless communication network, the detectiondevice comprising a receiver for acquiring radio signals fromcommunication units within the network, a communication interfacetowards another detection device for receiving information about radiosignal acquired by the another detection device, and a processorarranged for executing triangulation processing of data based onacquired signals.
 9. The device according to claim 8, further comprisinga transmitter arranged to send a signal triggering a re-establishment ofconnections between units in the wireless communication network.
 10. Thedevice according to claim 9, wherein the signal causing re-establishmentcomprises a jamming signal and a protocol command signal.
 11. The deviceaccording to claim 8, wherein the processor is further arranged toanalyze communication traffic between units in communication betweeneach other within the network.
 12. The device according to claim 8,further comprising a radio interface for acting as a base station forthe mobile units.
 13. The device according to claim 8, furthercomprising a direction sensitive antenna.
 14. A method for finding thenetwork structure of, or location of units in a wireless communicationnetwork, the method comprising the steps of: arranging a plurality ofreceivers for listening and identifying radio traffic in the wirelesscommunication network; obtaining communication traffic using theplurality of receivers; acquiring obtained communication traffic in acontrol unit; analysing the communication traffic in the control unit;and triangulating locations for the units within the network.
 15. Themethod according to claim 14, further comprising a step of forcingre-establishment of connections between the mobile stations and thecommunication network prior to acquiring communication traffic using theplurality of receivers.
 16. The method according to claim 14, furthercomprising the step of determining mutual connections between units inthe network.
 17. The method according to claim 14, further comprisingthe step of determining locations as coordinates in a map as well asheight information.
 18. A communication unit for operation in a wirelesscommunication network, comprising a communication interface and aprocessing unit arranged to transmit information stored in a memoryabout the communication unit to at least one stand alone positiondetection receiver.
 19. The communication unit according to claim 18,wherein the information stored about the communication unit comprises atleast one of ID of communication unit, ID of user, health information ofthe user, equipment related to the communication unit or the user, andstatus information of the user.